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Quality of light fittings
Slimy38 - 25/2/25 at 08:53 PM

For my car I bought a set of Ebay special Landrover dome lights. They suit my car, and yes I acknowledge that Ebay Chinese manufacturing was never going to be high quality. However, one of the light fittings just will not engage, the bulb bayonet will not lock in place.

The thing is, having looked at the bulbs I bought, they don't seem to be much better than the light fittings. For example, when I had my first car sometime last century, I remember the bayonet 'spikes' (or whatever they're called) being properly stuck out the side of the bulb. The ones in my current bulbs seem to be barely pressed out 'nubs' rather than something that could hold a bulb in place.

Have I got rose coloured memories of yesteryear, or has the race to the bottom of quality also affected the humble light bulb? Would I stand a better chance of working fittings with brand name bulbs?

I'm thinking of 3D printing the bulb holders and just keep hold of the lenses, lets hope I can print a bayonet mechanism that can function on bulb nubs that are about 0.75mm high.

gremlin1234 - 25/2/25 at 09:01 PM

yes 'value engineering' includes lightbulbs.

ie as cheep as possible

ps, I think the pins on bayonets are called barb's and a traditional bayonet has a long spiky bit on the front...

Mr Whippy - 25/2/25 at 09:06 PM

Buy LEDs, solder wires onto bulb & forget as will last longer than the car. I have done this with all the bulbs on my old car rather than faff with the old terminals.

Slimy38 - 25/2/25 at 09:55 PM

quote:
Originally posted by Mr Whippy
Buy LEDs, solder wires onto bulb & forget as will last longer than the car. I have done this with all the bulbs on my old car rather than faff with the old terminals.


I was thinking about LED's but I kind of like the old fashioned 'fade on fade off' effect. The very digital LED switch isn't quite the same.

Having said that, can you get LED rear and stop lights in one unit? Like the old twin-filament bulbs?

Slimy38 - 25/2/25 at 09:56 PM

quote:
Originally posted by gremlin1234
yes 'value engineering' includes lightbulbs.

ie as cheep as possible

ps, I think the pins on bayonets are called barb's and a traditional bayonet has a long spiky bit on the front...


Yeah I guess Bayonet Cap is a better description rather than simply a bayonet

Barbs makes sense though, thanks.

scudderfish - 26/2/25 at 06:50 AM

quote:
Originally posted by Slimy38
I was thinking about LED's but I kind of like the old fashioned 'fade on fade off' effect. The very digital LED switch isn't quite the same.


I wonder if a suitable capacitor could mimic that?

cliftyhanger - 26/2/25 at 07:49 AM

quote:
Originally posted by Slimy38
Having said that, can you get LED rear and stop lights in one unit? Like the old twin-filament bulbs?


I have bought a few sets (for different cars!) from classiccarleds. He sells a VERY bright, red twin filament stop/tail bulb but not cheap. On a small car it is a bonus as we often seem to get forgotton about.

SteveWalker - 26/2/25 at 10:52 AM

quote:
Originally posted by Slimy38
quote:
Originally posted by gremlin1234
yes 'value engineering' includes lightbulbs.

ie as cheep as possible

ps, I think the pins on bayonets are called barb's and a traditional bayonet has a long spiky bit on the front...


Yeah I guess Bayonet Cap is a better description rather than simply a bayonet

Barbs makes sense though, thanks.


Presumably the application of the term bayonet to light bulbs came from the "fitting" attaching bayonets to guns.

Initially bayonets (from the old French Bayonette, meaning knife, dagger, sword or similar) simply plugged into the barrels of guns - but this prevented them being fired and they could get stuck. Then a socket was developed, that when fitted to guns, allowed a bayonet to be fitted to the socket, rather than the barrel. The bayonet also had a double bend to offset the blade, making using the gun, while the blade was fitted, easier. Next the French added a spring, that kept the bayonet located in its twist-lock socket - effectively, the system used today for light bulbs.

And, indeed, the designation is BCxx - Bayonet Cap, plus the size in mm.

[Edited on 26/2/25 by SteveWalker]

Slimy38 - 26/2/25 at 03:39 PM

quote:
Originally posted by SteveWalker

And, indeed, the designation is BCxx - Bayonet Cap, plus the size in mm.

[Edited on 26/2/25 by SteveWalker]


I did also find the references 1156 and 1157, which led me to these holders;

https://www.ebay.co.uk/itm/387642422046

Still fairly cheap examples, but at least metal rather than the plastic I'm currently using.

coyoteboy - 26/2/25 at 04:29 PM

quote:
Originally posted by scudderfish
quote:
Originally posted by Slimy38
I was thinking about LED's but I kind of like the old fashioned 'fade on fade off' effect. The very digital LED switch isn't quite the same.


I wonder if a suitable capacitor could mimic that?


Not really, LEDs dim a little with lower voltage/current but they still just collapse at a point. You'd need a big cap, and an inline resistor of some sort, to get a half-ass mimic. There are ways with little circuits but not anything that will easily pop in a dome unless someone made a purpose-build circuit. These days the LEDs are PWM driven from the body control modules.

https://www.oznium.com/led-controllers/fade-in-fade-out?srsltid=AfmBOooVgWimGGz5dX0yWg5JZ6-aC2fQDRD1RtO7CA-2MPGOuHGlZ8tU

[Edited on 26/2/2025 by coyoteboy]